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From A J <s5a...@gmail.com>
Subject Re: Does the 'batch' order matter ?
Date Wed, 14 Mar 2012 22:22:01 GMT
> No, batch_mutate() is an atomic operation.  When a node locally applies a batch mutation,
either all of the changes are applied or none of them are.<
The steps in my batch are not confined to a single CF, nor to a single key.

The documentation says:
datastax:
Column updates are only considered atomic within a given record (row).

Pycassa.batch:
This interface does not implement atomic operations across column
families. All the limitations of the batch_mutate Thrift API call
applies. Remember, a mutation in Cassandra is always atomic per key
per column family only.


On Wed, Mar 14, 2012 at 4:15 PM, Tyler Hobbs <tyler@datastax.com> wrote:
> On Wed, Mar 14, 2012 at 11:50 AM, A J <s5alye@gmail.com> wrote:
>>
>>
>> Are you saying the way 'batch mutate' is coded, the order of writes in
>> the batch does not mean anything ? You can ask the batch to do A,B,C
>> and then D in sequence; but sometimes Cassandra can end up applying
>> just C and A,B (and D) may still not be applied ?
>
>
> No, batch_mutate() is an atomic operation.  When a node locally applies a
> batch mutation, either all of the changes are applied or none of them are.
>
> Aaron was referring to the possibility that one of the replicas received the
> batch_mutate, but the other replicas did not.
>
> --
> Tyler Hobbs
> DataStax
>

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